[Hurtak]

You could combine the 'turn off css snippet' with something like this:

document.body.insertAdjacentHTML('afterbegin', '<style>{outline: 1px solid black}</style>')

both together:

javascript:[].slice.call(document.querySelectorAll('link,style,[style]')).forEach(function(e){e.style.cssText?e.style.cssText='':e.outerHTML=''});document.body.insertAdjacentHTML('afterbegin', '<style>{outline: 1px solid black}</style>');